[OS X TeX] The `%!TEX TSprogram = TeXify' line used in TeXShop ...
amorton at fastmail.fm
Thu Feb 14 01:43:07 EST 2008
> For decades just %! has been the "magic number" for Postscript files
> and Postscript data streams. Any additional data after the %!
> simply specifies additional information about the Postscript code
> contained in the file and is not required.
Actually, %! has been used as a lazy identifier for *non-conforming*
Postscript - any conforming Postscript has to start with %!PS-Adobe-
<num> at the very least. Even most non-conforming Postscript will
start with a %!PS identifier.
> It is TeXshop, with its %!TEX, that is at fault. This is not a
> "magic number" used to identify a type of file. It is a TeXShop hack
> attempting to pass various parameters to TeXShop from source files
> and is incompatible with the use of magic numbers.
OK, but this heinous crime isn't specific to the TeXShop team - the
Sunclock people have used %!VMF for their vector map files for years
and this is recognised in the magic file distributed on most systems.
It's a fairly intuitive way to specifiy a file format for any language
that uses % for comments.
> The developers of TeXShop really need to change %!TEX to something
> else, %%!TEX has been suggested on this list. Of course, this would
> cause backward compatibility issues for some TeXShop users. Those
> affected should not blame anyone but the developers of TeXShop who
> did not consider all of the ramifications of using %!TEX.
But of course the file still won't be identified as LaTeX source
unless you add the %%!TEX or whatever to the magic file - it's still
expecting /documentclass or some similar command on the first line of
the file. If you have to modify the magic database anyway you might
as well get it to recognise %!TEX which has been established as a de
facto standard for some time now.
It's long been recognised that the magic-number system is fragile and
anyone relying on it needs to be on the lookout for special cases that
require updating the database.
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